Structure and Mechanical Properties of Ni-P-Nano Al_2O_3 Composite Coatings Synthesized by Electroless Plating

摘要

Ni-P-nano Al_2O_3 composite coatings were deposited by electroless plating, and their microstructures were observed by SEM (scanning electron microscope). The microhardness and the wear resistance of the Ni-P-nano Al_2O_3 composite coatings were measured using microhardness tester and block-on-ring tribometer, respectively, and the comparison with those of Ni-P coatings or Ni-P-micro Al_2 O_3 coating was given. The influences of aging temperature on their hardness and wear resistance were analyzed. The results showed that the nano Al_2O_3 particles were distributed uniformly in the Ni-P-Al_2O_3 coatings. Among three kinds of Ni-P based coatings, the hardness and wear resistance of Ni-P-nano Al_2O_3 coatings were largest, and the maximum values could be obtained at 400 ℃. This indicated that the precipitation of nano Al_2O_3 particles would improve the hardness and wear resistance of the Ni-P coatings.